Eventually, when your immune system is so decimated that you are susceptible to the opportunistic infections mentioned in the beginning of this article, you will have developed full-blown AIDS. These are diseases that would never bother you if you had a healthy immune system.
Some of the symptoms of these infections include night sweats, fever and chills, chronic diarrhea, cough and shortness of breath, weight loss (for many years, the syndrome was referred to as The Wasting Disease in many African countries, due to the amount of weight lost by a victim), body and head aches, blurred vision, skin rashes or bumps, and white patches on your tongue. As AIDS progresses further, patients may also experience pneumonia, tuberculosis, herpes, other viral conditions and certain cancers -- most commonly Kaposi's sarcoma.
Not a pretty picture, but definitely a preventable one. HIV/AIDS is quite complex.